﻿using System.Collections;
using System.Windows.Forms;
using System;

/// <summary>
/// This class is an implementation of the 'IComparer' interface.
/// </summary>
namespace Ession
{
    public class ListViewColumnSorter : IComparer
    {

        /// <summary>
        /// Class constructor.  Initializes various elements
        /// </summary>
        public ListViewColumnSorter()
        {
            // Initialize the column to '0'
            ColumnToSort = 0;

            // Initialize the sort order to 'none'
            OrderOfSort = SortOrder.None;

            // Initialize the CaseInsensitiveComparer object
            ObjectCompare = new CaseInsensitiveComparer();
        }
        public int SortType = 0; //排序方式：0：按字符串排序 1：按数字 2：按日期

        /// <summary>
        /// Specifies the column to be sorted
        /// </summary>
        private int ColumnToSort;
        DateTime dTime1, dTime2;
        /// <summary>
        /// Case insensitive comparer object
        /// </summary>
        private CaseInsensitiveComparer ObjectCompare;
        /// <summary>
        /// Specifies the order in which to sort (i.e. 'Ascending').
        /// </summary>
        private SortOrder OrderOfSort;

        /// <summary>
        /// Gets or sets the order of sorting to apply (for example, 'Ascending' or 'Descending').
        /// </summary>
        public SortOrder Order
        {
            set
            {
                OrderOfSort = value;
            }
            get
            {
                return OrderOfSort;
            }
        }

        /// <summary>
        /// Gets or sets the number of the column to which to apply the sorting operation (Defaults to '0').
        /// </summary>
        public int SortColumn
        {
            set
            {
                ColumnToSort = value;
            }
            get
            {
                return ColumnToSort;
            }
        }
        /// <summary>
        /// This method is inherited from the IComparer interface.  It compares the two objects passed using a case insensitive comparison.
        /// </summary>
        /// <param name="x">First object to be compared</param>
        /// <param name="y">Second object to be compared</param>
        /// <returns>The result of the comparison. "0" if equal, negative if 'x' is less than 'y' and positive if 'x' is greater than 'y'</returns>
        public int Compare(object x, object y)
        {
            int compareResult;
            ListViewItem listviewX, listviewY;

            // Cast the objects to be compared to ListViewItem objects
            listviewX = (ListViewItem)x;
            listviewY = (ListViewItem)y;

            // Compare the two items
            //    compareResult = ObjectCompare.Compare(listviewX.SubItems[ColumnToSort].Text, listviewY.SubItems[ColumnToSort].Text);


            if (this.SortType == 1)
            { //按数字
                compareResult = int.Parse(listviewX.SubItems[ColumnToSort].Text) - int.Parse(listviewY.SubItems[ColumnToSort].Text);
            }
            else
                if (this.SortType == 2)
                { //按日期
                    try
                    {
                        dTime1 = System.DateTime.Parse(listviewX.SubItems[ColumnToSort].Text);
                    }
                    catch
                    {
                        dTime1 = new DateTime(1800, 1, 1, 1, 0, 0, 0);
                    }

                    try
                    {
                        dTime2 = System.DateTime.Parse(listviewY.SubItems[ColumnToSort].Text);
                    }
                    catch
                    {
                        dTime2 = new DateTime(1800, 1, 1, 1, 0, 0, 0);
                    }
                    compareResult = System.DateTime.Compare(dTime1, dTime2);
                    //return System.DateTime.Compare(System.DateTime.Parse(listItemA.SubItems[columnNum].Text), System.DateTime.Parse(listItemB.SubItems[columnNum].Text));
                }
                else
                {
                    //按字符串
                    compareResult = ObjectCompare.Compare(listviewX.SubItems[ColumnToSort].Text, listviewY.SubItems[ColumnToSort].Text);
                }


            // Calculate correct return value based on object comparison
            if (OrderOfSort == SortOrder.Ascending)
            {
                // Ascending sort is selected, return normal result of compare operation
                return compareResult;
            }
            else if (OrderOfSort == SortOrder.Descending)
            {
                // Descending sort is selected, return negative result of compare operation
                return (-compareResult);
            }
            else
            {
                // Return '0' to indicate they are equal
                return 0;
            }
        }

    }
}

